Rotating components can excite the structural resonances of themselves or of nearby components due to an excitation force at some multiple of the rotation speed. These resonances cause unwanted vibration and noise resulting in discomfort for individuals nearby as well as reducing the durability and performance of the affected components.
Therefore, systems are characterized so the speeds that excite resonances are avoided. Avoiding resonance reduces noise and vibration and resulting machinery damage. However, because of manufacturing variances, the use of temperature-sensitive plastics in temperature-varying environments, or a lack of knowledge of what the rotating-component ultimately attaches to, the resonances of many systems cannot be fully characterized, and a preemptive approach to avoiding resonances cannot be achieved.